If you actually watched him, you would know that he takes on a lot of hard hitting issues.
It is a comedy show, but it's not there to educate you on these subjects. It is there to pique your intrest, and to inform you that an alternate way of looking at the subject exists, and you should go learn more about it.
Is he any more or less biased than any other journalist out there? Everything in this video was factual. Do you have criticisms of the actual content besides that it was entertaining?
Edit: re: "investigations"
This isn't investigative reporting. You could have put the information in this segment together sans comedian from your laptop with probably 20 minutes of googling. It's all well known facts that are out there that he's bringing to the surface.
It is a comedy show, but it's not there to educate you on these subjects. It is there to pique your intrest, and to inform you that an alternate way of looking at the subject exists, and you should go learn more about it.